HOUSTON — Before the All-Star break, Yankees manager Aaron Boone said he hoped a few days off would benefit the slumping Joey Gallo and allow him to “exhale” following a brutal first half. 

After being booed in The Bronx, Gallo had homered in his final game before the break, which followed a 4-for-55 stretch in which the outfielder had just two extra-base hits and 14 walks to go along with 27 strikeouts over 21 games. 

Gallo continued to slump in the first game after the break, as he went hitless again in the Yankees’ 3-2 loss to the Astros at Minute Maid Park in the first game of a split doubleheader. He didn’t play in the nightcap, a 7-5 Yankees loss. 

In the top of the second inning, Gallo hit a high pop to shortstop with Aaron Hicks on second base. He then hit a 107 mph fly ball to right that found Kyle Tucker’s glove in the fifth and struck out looking in the seventh. Gallo also drew a two-out walk to load the bases in the top of the ninth, after Isiah Kiner-Falefa had tied the score with a run-scoring single. 

In the nightcap, he was benched in favor of light-hitting righty Tim Locastro with Luis Garcia, a right-hander, on the mound. 

Still, it was another day without a hit for Gallo, whose time with the Yankees could well be numbered as the Aug. 2 trade deadline approaches. 

Gallo has said he doesn’t want to be traded, but the Yankees seem to have little choice because the slugger has not found his footing since arriving in a trade from the Rangers nearly a year ago. 

Boone said he was encouraged by Aroldis Chapman’s scoreless seventh inning in the second game. The struggling lefty had given up runs in two of his previous three appearances, but he has had an uptick in strikeouts, adding two more on Thursday. 

“There was a lot of good in there,’’ Boone said. “What he threw out there tonight is real. We’ve just got to get him consistently back to that point of having a lot of faith in that fastball.”